Development of the hybridoma technology [Kohler, G., and C. Milstein, (1975) Nature 256:495 and; Goding, J. W., (1980) Immunological Methods 39:285] has provided immunoglobulin reagents which bind to only one antigenic site. Although these reagents have found widespread use as biochemical and immunological tools, their usefulness in radioimmunoassay has frequently been limited by their lower affinity for antigen compared with that of serum antibodies [Goding, J. W., (1980) Immunological Methods 39:285]. In principle, the affinity of monoclonal antibodies could be enhanced by more stringent hybridoma selection procedures. The production of monoclonal antibodies has also enabled investigators to dissect the humoral immune response into its pure components [Staines, N. A. and A. M Lew (1980), Immunology 40:287]. This will eventually result in a more comprehensive understanding of the role of the individual antibody, especially with regard to the possibility that an antiserum may have different characteristics than the sum of its individual antibodies.
During the course of a systematic assessment of the immunochemistry of human chorionic gonadotropin (hCG), including the relative orientation of different epitopes of this molecule and the effect of several monoclonal antibodies on the hormone-receptor interaction, it has been observed that the apparent affinity of mixtures of certain monoclonal antibodies is enhanced relative to the affinity of the individual antibodies.